Phase-controlled synthesis of bismuth oxide polymorphs for photocatalytic applications

2018 ◽  
Vol 2 (9) ◽  
pp. 1664-1673 ◽  
Author(s):  
Thangavel Selvamani ◽  
Sambandam Anandan ◽  
Luis Granone ◽  
Detlef W. Bahnemann ◽  
Muthupandian Ashokkumar

Bismuth oxide polymorphs (β-Bi2O3 nanoparticles and α-Bi2O3 coral-like morphology) were synthesized and they show an enhanced efficacy for the degradation of rhodamine B and acid orange 7 as compared to that of methylene blue and methyl orange under simulated solar illumination.

2019 ◽  
Vol 48 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Meng-Jung Tsai ◽  
Jheng-Hua Luo ◽  
Jing-Yun Wu

A rhombus (4,4) grid showing two-fold 2D + 2D → 2D interweaved nets appeared to be a good adsorbent to selectively adsorb and separate anionic methyl orange (MO) and acid orange 7 (AO7) dyes over cationic methylene blue (MB) and malachite green (MG) from water with high adsorption capacities in both darkness and daylight.


Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 586 ◽  
Author(s):  
Zhang ◽  
Park

A series of ultralong (up to tens of micrometers) MoO3 nanowire-based membranes were synthesized for the treatment of aqueous solutions containing the cationic dyes methylene blue (MB) and rhodamine B (RhB). This treatment method possesses extremely rapid and superhigh adsorbability (up to 521 and 321 mg/g for MB and RhB, respectively), as well excellent selective adsorption ability of cationic dyes with respect to the anionic dye methyl orange (MO). Moreover, the cationic dyes on the membrane can be desorbed easily, and reusability is good.


2013 ◽  
Vol 330 ◽  
pp. 112-116 ◽  
Author(s):  
Nabilah A. Lutpi ◽  
N. Najihah Jamil ◽  
C.K. Kairulazam C.K. Abdullah ◽  
Yee Shian Wong ◽  
Soon An Ong ◽  
...  

The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) dye onto Ananas Comosus Mixed Peels and Leaves (ACMPL) were carried out by conducting four different parameters such as initial concentration, pH, dosage of adsorbent, and contact time. Effect of initial concentration for both dyes showed that higher initial concentration would take longer contact time to attain equilibrium due to higher amount of adsorbate molecules. The effect of pH showed highest percentage removal for MB is at pH 9 which is 95.81%. Meanwhile for AO7 the highest percentage removal is 31.06% at pH 3. The percentage removal of MB had reached the equilibrium at dosage 0.5g while AO7 keep increasing with the increment of adsorbent dosage. The percentage removal of MB and AO7 had increased until hour 2.5 which was from 72.5% to 86.93% and 19.441% to 36.89% respectively and reached equilibrium at 3 hour contact time.


2018 ◽  
Vol 156 ◽  
pp. 05019 ◽  
Author(s):  
Eko Andrijanto ◽  
Gatot Subiyanto ◽  
Nina Marlina ◽  
Hanifa Citra ◽  
Cahya Lintang

This paper describes a method to synthesize a graphene oxide sand composites (GSC) as filter media (absorbent) for water purification. Graphene oxides is synthesized from graphite using modification of Hummer's method. The graphene oxide sand composites is prepared through solution method at 100 °C. The graphene oxide is analyzed using XRD, FTIR to confirm its formation. The FTIR spectrum and XRD diffraction pattern confirmed that the graphene oxide synthesized by this method is able to convert graphite into graphene oxide. Performance tests were conducted using a column to purify contaminated water which was mimicked using dyes such as rhodamine B, methylene blue and methyl orange.The initial concentration for all dyes were set for 5, 10, 25, 50 and 100 ppm. The color removal for methylene blue was 100% at all concentrations. However, for the rhodamine B and methyl orange, the color removal achieved 100% for the first three concentration 5, 10 and 25 ppm. The higher concentration of 50 and 100 ppm, the removal were slightly reduced. For the 50 ppm, the color removal of rhodamine B was 98% and for methyl orange 87% respectively. At 100 ppm, the color removal for rhodamine B drops to 92% and for the methyl orange was only 77% respectively. The GSC was very effective to remove methylene blue dyes at any concentration followed by rhodamine B and methyl orange. This GSC composite material is potential to be applied for water purification.


2021 ◽  
Vol 21 (4) ◽  
pp. 2483-2494
Author(s):  
Aqeel Ahmed Shah ◽  
Ali Dad Chandio ◽  
Asif Ahmed Sheikh

The design of sensitive and efficient photo catalyst for the energy and environmental applications with minimum charge recombination rate and excellent photo conversion efficiency is a challenging task. Herein we have developed a nonmetal doping methodology into ZnO crystal using simple solvothermal approach. The boron (B) is induced into ZnO. The doping of B did not make any significant change on the morphology of ZnO nano rods as confirmed by scanning electron microscopy (SEM) without considerable change on periodic arrangement of nanostructures. The existence of B, Zn, and O is shown by energy dispersive spectroscopy (EDS). The X-ray diffraction (XRD) patterns are well matched to the hexagonal phase for both pristine ZnO and B-doped ZnO. The XRD has shown slight dislocation of 2theta degree. The UV-visible spectroscopy was used to measure the optical bandgap and photo catalytic activity for the degradation of organic dyes. The nonmetal doped ZnO has shown potential and outstanding photo catalytic activity for the photo degradation of methylene blue (MB), methyl orange (MO) and rhodamine B in aqueous solution. The photo degradation efficiency of MB, MO and rhodamine B is found to be 96%, 86% and 80% respectively. The enhanced photo catalytic activity of B-doped ZnO is indexed to the inhibited charge recombination rate due to the reduction in the optical bandgap. Based on the obtained results, it can be said that nonmetal doping is excellent provision for the design of active materials for the extended range of applications.


2017 ◽  
Vol 81 ◽  
pp. 282-290 ◽  
Author(s):  
Jin-Gang Yu ◽  
Jiao Zou ◽  
Liang-Liang Liu ◽  
Xin-Yu Jiang ◽  
Fei-Peng Jiao ◽  
...  

2006 ◽  
Vol 53 (11) ◽  
pp. 163-171 ◽  
Author(s):  
N. Yemashova ◽  
S. Kalyuzhnyi

Four selected azo dyes (acid orange 6, acid orange 7, methyl orange and methyl red) were completely decolourised in the presence of anaerobic granular sludge, while only methyl red was degraded in aerobic conditions using a conventional activated sludge. Additional experiments with culture broth devoid of cells showed that anaerobic decolourisation of azo dyes was performed by extracellular reducing agents produced by anaerobic bacteria. This was further confirmed by abiotic experiments with sulphide and NADH. The presence of redox mediators such as riboflavin led to dramatic acceleration of the anaerobic biodecolourisation process. The azo dye reduction products were found to be sulphanilic acid and 4-aminoresorcinol for acid orange 6; sulphanilic acid and 1-amino-2-naphthol for acid orange 7; N,N-dimethyl-1,4-phenylenediamine and sulphanilic acid for methyl orange; and N,N-dimethyl-1,4-phenylenediamine and anthranilic acid for methyl red. Anaerobic toxicity assays showed that the azo dyes were more toxic than their breakdown products (aromatic amines), except 1-amino-2-naphthol. In the presence of activated sludge, only anthranilic acid was completely mineralised while sulphanilic acid was persistent. 4-aminoresorcinol, 1-amino-2-naphthol and N,N-dimethyl-1,4-phenylenediamine underwent autooxidation in aerobic conditions yielding coloured polymeric products. On the contrary, in the presence of granular methanogenic sludge, 4-aminoresorcinol, 1-amino-2-naphthol and anthranilic acid were quantitatively methanised, sulphanilic acid was partially (70%) mineralised while N,N-dimethyl-1,4-phenylenediamine was only demethylated producing 1,4-phenylenediamine as an end product.


2016 ◽  
Vol 75 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Borja Rodríguez-Cabo ◽  
Iago Rodríguez-Palmeiro ◽  
Raquel Corchero ◽  
Rosario Rodil ◽  
Eva Rodil ◽  
...  

The photocatalytic degradation of wastewater containing three industrial dyes belonging to different families, methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB), was studied under UV-Vis irradiation using synthesised silver chloride nanoparticles. The nanocatalyst was prepared by a dissolution/reprecipitation method starting from the bulk powder and the ionic liquid trihexyl(tetradecyl)phosphonium chloride, [P6 6 6 14]Cl, without addition of other solvents. The obtained catalyst was characterised by UV-Vis absorbance, X-ray powder diffraction, transmission electron microscopy and scanning electron microscopy. The decolourisation of the samples was studied by UV-Vis absorbance at the corresponding wavelength. Starting from 10 ppm dye solutions and 1 g L−1 of the synthesised AgCl nanoparticles, degradation efficiencies of 98.4% for MO, 98.6% for MB and 99.9% for RhB, were achieved in 1 h. The degradation mechanisms for the different dyes were studied. Comparison with other frequently used nanocatalysts, namely P-25 Degussa, TiO2 anatase, Ag and ZnO, highlights the strong catalytic activity of AgCl nanoparticles. Under the same experimental conditions, these nanoparticles led to higher (more than 10%) and faster degradations.


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